so i finally got a dyno tune from jeremy formatto..it put down 335rwhp 327rwtq..mods, dunno if they are in my sig..ported heads/intake..XE 218/230..pacesetter LTs flowmaster catback..gears and CAI...anyways..he tuned the car etc etc then we take it out for some WOT testing..now it wont shift..we thought it was the rev limtied but according to his laptop it was not since the rev limtier was set at 6500..it sounds exactly like the rev limiter around 5900 except he said its spark blow out? he says i need to switch to NGK TR6's and seafoam my car..the car will break up or whatever it is it does for a few seconds then go into the next gear..will the new plgus and seafoam cure the car or does anyone else have an idea

 

I wouldn't have any idea, but are those good springs your using, and are they set up correctly? Who adjusted your rockers? My car did the same thing. Motor peaked around 5900 to 6000 on the dyno. So the shift points were set about 6200. Didn't know that anything over 6k lead to valve float with the springs I had at the time. So now the motor can't reach the shift point or delays a small amount of time before it shifted. Tuner lowers shift points and every thing is fine or so I thought. A few months later the car is back on the dyno and and it would not pull as high. So this is where we figured out the motor needed better springs (918s). Peak power is 6k and hardly falls up to 6400. So now the 1-2 shift is 6400 and the 2-3 shift is 6300. Can't wait to get back to the track with the improved RPM and the light weight Bogart wheels I bought. Sorry this reply was so long, but just thought I'd give you at least thing to look for with your problem. Good Luck.

 

Did this all happen after this tune? Are those numbers with the converter unlocked? If they are, they are right in line with your mods. Proper valvespring pressure is absolutely crucial with hydraulic rollers like the above post pointed out. Or, lifter preload could be too tight.

 

it has a stock converter..the springs are isky 235-D

 

I'm gonna guess that you don't have enough spring.

 

the sprigns are rated to .550

 

Lift rating doesn't mean they have enough spring pressure to control the valves. And what installed height did you put them in at.